Simon Mostyn
has recently married Kay Ridgeway, a rich woman, having thrown over his
former lover Jacqueline. The couple are on their honeymoon and are at
present on a paddle steamer on the Nile. With them is Canon Pennefather,
Kay's guardian, and Jacqueline, who has been dogging their footsteps all
through the honeymoon. Also on the boat are a rich, ill tempered old
woman with her niece and companion, a rather direct young man, a German
who nurses a grudge against Kay's father and Kay's maid. During the
voyage Jacqueline works herself into a state of hysteria and shoots at
Simon, wounding him in the knee. A few moments later Kay is found shot
in her bunk. By the time the boat reaches its destination, Canon
Pennefather has laid bare an audacious conspiracy and has made sure the
criminals shall not go free.